Cutting-edge structures and method of manufacturing cutting-edge structures

ABSTRACT

A novel cutting-edge structure and method and apparatus for manufacturing the cutting-edge structure is provided. The cutting-edge structure is comprised of naturally derived or renewable material at greater than 50% by volume fraction. In one embodiment, the naturally derived material is a cellulose nanostructure such as a cellulose nanocrystal. The cellulose nanocrystal is processed using a base or mold structure to provide a cutting edge of any shape such as linear or circular edge structures. The process includes dual cure steps to produce an optimal cutting-edge structure without shrinkage. The formed cutting-edge structure can be utilized as a razor blade as it is formed with very sharp tip and edge suitable for cutting hair. The base structure can form one or more cutting-edge structures simultaneously.

CROSS-REFERENCE TO RELATED APPLICATION

The present invention is related to co-pending U.S. Docket Number101328-562 filed on the same date Dec. 12, 2019, U.S. application Ser.No. ______, as the present application, and U.S. Application Ser. No.62/780,187 filed on Dec. 14, 2018. “Systems, Devices, and Methods forBulk Processing of Highly-Loaded Nanocomposites,” incorporated herein inits entirety, including specification and drawings.

FIELD OF THE INVENTION

This invention relates to shaving razors and methods of manufacturingcutting-edge structures, and more particularly to manufacturingcutting-edge structures such as shaving razor blades from naturallyderived, renewable, or biodegradable materials.

BACKGROUND OF THE INVENTION

Razor blades are typically formed of a suitable metallic sheet materialsuch as stainless steel, which is slit to a desired width andheat-treated to harden the metal. The hardening operation utilizes ahigh temperature furnace, where the metal may be exposed to temperaturesgreater than about 1000° C. for up to about 20 seconds, followed byquenching, whereby the metal is rapidly cooled to obtain certain desiredmaterial properties.

After hardening, a cutting-edge is formed generally by grinding theblade. The steel razor blades are mechanically sharpened to yieldcutting-edges that are sharp and strong to cut through hair over anextended period of time. The continuous grinding process generallylimits blade shapes to have straight edges with a substantiallytriangular or wedge-shaped profile (e.g., cross section). Thecutting-edge wedge-shaped configuration typically has an ultimate tipwith a radius less than about 1000 Ångstroms.

The advantage of this prior art method is that it is a proven,economical process for making blades in high volume at high speed. Itwould be particularly desirable if such a process could utilize lowercost materials for blade formation and also enable other cutting-edgeprofiles.

Blades with cutting-edges made from a polymeric material are disclosedfor disposable cutlery or disposable surgical scalpels (e.g., U.S. Pat.Nos. 6,044,566, 5,782,852). Razor blades made from polymeric materialare disclosed in GB2310819A, and US20470001325A1. The disadvantages ofthe prior art relating to polymer blades include difficulty in obtainingdesired mechanical properties in conventional polymeric material andthat the polymeric blades are not comprised of materials that aresubstantially derived from or comprised of, naturally derived, renewableor biodegradable sources or materials.

Consumers, industry, and government are increasingly demanding productsmade from renewable and sustainable resources that have one or more ofthe following beneficial attributes: biodegradable, non-petroleum based,carbon neutral, and having low environmental, animal/human health andsafety risks. The advantage to having blades made from novel materialsthat are sustainable or renewable is the beneficial impact to theenvironment, where instead of filling up landfills, these products areeasily disposed due to their ability to break down in the earth or theirability to be recycled.

Therefore, there is a need to produce a razor blade cutting edge that issubstantially renewable and that is also suitable (e.g., sharp enough)to cut hair (e.g., a cutting-edge having a tip radius of less than 1 μmas required for cutting hair).

A need exists for improved processes for cutting-edge structurescomprised of naturally derived polymers and more cost-effective methodsof making cutting-edge structures for shaving razors having required tipradius, optimal edge quality and sharpness to provide a comparable orimproved shaving experience.

It is also desirable to find materials and processes that can formcutting-edge structures having any shape, such as non-linear edgesand/or provide an integrated razor assembly.

SUMMARY OF THE INVENTION

The present invention provides a simple, efficient method formanufacturing, including molding, one or more cutting-edge structures,such as razor blades from a renewable or sustainable material and afunctional cutting-edge structure such as a razor blade. Moreover, somemethods are suitable for producing a plurality of such cutting-edgestructures, or “blade boxes” comprising a plurality of razor bladesformed of this naturally derive, renewable, or biodegradablecutting-edge structure material to be disposed as a single unit in arazor cartridge.

In one aspect, the method for manufacturing at least one cutting-edgestructure includes providing the steps of:

-   -   a. providing a base structure having a first and a second        portion;    -   b. providing one or more physical gels;    -   c. curing the one or more physical gels to form one or more        chemical gels;    -   d. inserting the one or more chemical gels into the first        portion of the base structure;    -   e. curing the one or more chemical gels one or more times,        forming a dried chemical gel;    -   f. contacting the dried chemical gel with the second portion of        the base structure;    -   g. forming the cutting-edge structure during the contacting        step.

The physical gel includes a naturally derived material.

In another aspect, the physical gel includes one or more naturallyderived materials, renewable materials, biodegradable materials, one ormore solvents, at least one polymeric material, or any combinationthereof.

The one or more naturally derived materials include cellulosenanostructures. The cellulose nanostructures include cellulosenanocrystals. The one or more solvents include an organic material. Theorganic material includes dimethylformamine. The cellulosenanostructures include naturally derived materials.

In another aspect, the at least one polymeric material includes one ormore epoxides. Further, the step of curing the one or more chemical gelsincludes evaporation of the one or more solvents; the step of contactingthe dried chemical gel with the second portion further includescontacting the first portion of the base structure.

The step of contacting the dried chemical gel includes a line contact atan interface of the first and second portions of the base structure.

The curing steps include heat, light, or a combination thereof. Thelight includes ultra-violet (UV) light. The physical gel furtherincludes one or more cross-linkers, one or more photo-initiators, or anycombination thereof. The one or more photo-initiator includes anultra-violet light curing photo-initiator. The heat includes a thermalcross-linker comprising polyamine. The ultra-violet light curingphoto-initiator includes an epoxide.

In a further aspect, the step of curing the one or more physical gels toform one or more chemical gels includes repeating the step of providingone or more physical gels and the step of curing the one or morephysical gels to form one or more chemical gels.

In yet a further aspect, the step of curing the one or more chemicalgels includes curing at a temperature up to about 50 degrees Celsius toabout 100 degrees Celsius for a first duration and curing at atemperature up to about 120 degrees Celsius to about 180 degrees Celsiusfor a second duration.

Still further, the method further includes the step of releasing thecutting-edge structure from the base structure and a step of insertingthe cutting-edge structure into a razor cartridge, a blade box, a frame,or any combination thereof.

In a still further aspect, the formed cutting-edge structure includes acircular or linear shape and a brown color. Still another aspect, thecellular nanocrystals are aligned vertically, horizontally, or in amixed manner within the cutting-edge structure.

In another embodiment of the present invention, a cutting-edge structureincludes one or more naturally derived materials. The cutting-edgestructure may also include one or more solvents, one or more renewablematerials, one or more biodegradable materials, one or more polymericmaterials, or any combinations thereof.

The one or more naturally derived materials include cellulosenanostructures, wherein the cellulose nanostructures are cellulosenanocrystals. The one or more solvents include an organic material. Theorganic material includes dimethylformamine. The at least one polymericmaterial includes one or more epoxides.

In another aspect, the cutting-edge structure includes a brown color,and a shape that is circular, linear, or any combination thereof. Instill other aspects, 100% of the cutting-edge structure is comprised ofthe one or more naturally derived materials by volume fraction, 100% ofthe cutting-edge structure is comprised of one or more renewable sourcesby volume fraction, about 50% to about 100% of the cutting-edgestructure is comprised of naturally derived materials by volumefraction, about 50% to about 100% of the cutting-edge structure iscomprised of renewable materials by volume fraction, or about 50% toabout 100% of the one or more naturally derived materials by volumefraction.

In another embodiment, the one or more naturally derived materialsinclude a majority of the cutting-edge structure by volume fraction. Thecutting-edge structure includes a tip radius of less than about 1 um.The cutting-edge structure is biodegradable.

In a third embodiment of the present invention, an apparatus formanufacturing at least one cutting-edge structure comprises a firstportion and a second portion and one or more naturally derivedmaterials. In one aspect, one of the portions includes a cylindricalshape.

The first portion is a plunger structure and the second portion is acavity structure. The plunger structure further includes a plungerelement and a plunger body. The plunger structure further includes arelief portion wherein the relief portion is disposed between theplunger body and the plunger element. The relief portion enables a pointor line contact between a plunger structure and a cavity structure tomold the naturally derived material into a cutting-edge structure. Theplunger structure further includes an angled surface. At least a portionof the plunger structure includes a cylindrical shape.

In a further aspect, the plunger structure comprises one or morelubricious materials, one or more plastic materials, one or more metals,or any combinations thereof. The lubricious material includes Teflon.

Still further, the cavity structure includes an aperture. The apertureextends through the cavity structure. The cavity includes a circularshape. The cavity structure includes angled surfaces. The first portion,the second portion, or both the first portion and second portion includeone or more lubricious materials, one or more plastic materials, one ormore metals, or any combinations thereof. The lubricious material of thecavity structure includes Teflon.

The present invention step of curing includes cross-linking orpolymerization and the curing step is mediated via heat, light, such asUV light, or a combination thereof.

In still yet another aspect of the invention, the at least onecutting-edge structure formed using the method herein is a razor bladeor a portion of a blade box and the razor blade or the blade box issecured into a razor cartridge housing or frame. The blade box may becomprised of different types of cutting-edge structures.

Another embodiment of the present invention includes a blade boxcomprising at least one cutting-edge structure, at least onenon-cutting-edge structure coupled to said at least one cutting-edgestructure, both the cutting and non-cutting-edge structures comprised ofa renewable material such as a cellulose nanostructure material.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a desired sustainable cutting-edge material of thepresent invention, namely a cellulose nanostructure.

FIGS. 2A, 2B, and 2C depicts the chemical and physical structure of thecellulose nanostructure of the present invention.

FIGS. 3A, 3B, and 3C depict exemplary illustrations of microstructuralarrangements of cellulose nanocrystals in razor blade embodiments of thepresent invention.

FIG. 4 depicts a schematic view of portions of a base structure of thepresent invention.

FIG. 5 depicts a schematic view of the portions of the base structure incontact with each other and the cutting-edge material of the presentinvention.

FIG. 5A depicts a photographic image of the portions of the basestructure of the present invention.

FIG. 6 depicts an illustration of a razor blade cutting-edge structureof the present invention formed using the base structure of FIGS. 4 and5.

FIG. 7 depicts a photographic image of a portion of the base structureand the cutting-edge structure formed in the present invention.

FIG. 8 is a micrograph of a portion of a cutting-edge structure having aloop shape formed of cellulose nanostructure material according to thepresent invention.

FIGS. 9A and 9B depict illustrations of another embodiment of a basestructure of the present invention for forming linear shapedcutting-edge structures.

FIG. 9C depicts an illustration of yet another embodiment of a basestructure of the present invention for forming linear shapedcutting-edge structures.

FIG. 9D depicts an illustration of a linear shaped cutting-edgestructure of the present invention.

FIG. 10 depicts a razor blade cartridge comprising linear shapedcutting-edge structures of the present invention.

FIG. 10A depicts a razor blade cartridge comprising circular shapedcutting-edge structures of the present invention.

FIG. 11 depicts an embodiment of the cutting-edge material of thepresent invention comprising cellulose nanostructures, epoxide, andsolvent.

FIGS. 12A and 12B are flow diagrams of methods of manufacturing razorblades from the novel cutting-edge material, according to a preferredembodiment of the present invention.

FIGS. 13A to 13C depict schematic diagrams of an alternate basestructure of the present invention.

FIG. 14 depicts multiple cutting-edge structures formed as a group inaccordance with the present invention.

FIGS. 14A and 14B depict coatings deposited on cutting-edge structuresin accordance with the present invention.

FIG. 15 depicts multiple cutting-edge structures formed as a groupinserted into a razor cartridge in accordance with the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides for cutting-edge structures (e.g., razorblades which may be used in shaving devices or razors) and methods formanufacturing cutting-edges or razor blades for shaving devicescomprising naturally derived materials comprising nanostructures.

The cutting-edge structures of the present invention are substantiallyformed from naturally derived, renewable, or biodegradable materials.

As used herein, “renewable” is a term that generally signifies arenewable resource is one which can be replaced naturally in arelatively short time or replenished with time, like the growth of neworganisms or the natural recycling of materials. Literally the termmeans ‘to make new again. Renewable resources do not have a fixedquantity—more can always be generated. For instance, wood from managedsoftwood forests is renewable, because these trees can be regrown in afew years.

The term “substantially” as used herein signifies to a great orsignificant extent.

The term “sustainable” as used herein, signifies of, relating to, orbeing a method of harvesting or using a resource so that the resource isnot depleted or permanently damaged.

If the rate of use of a source exceeds the rate of renewal (e.g., thesource is used more than it is being recreated), its continued use willbecome unsustainable.

The term “biodegradable,” as used herein, signifies that a substance orobject is capable of being decomposed by bacteria or other livingorganisms. Biodegradable substances include food scraps, cotton, wool,wood, human and animal waste, manufactured products based on naturalmaterials (such as paper, and vegetable-oil based soaps).

The term “naturally derived,” as used herein, indicates that some or allingredients are derived from nature that have been used to create aproduct, the latter in and of itself not originally occurring or formedin nature.

The materials of the present invention preferably comprisenanostructures. Cellulose nanocrystals are an example of a naturallyderived, widely available, biodegradable nanostructure with optimalmechanical properties. Other nanostructures contemplated in the presentinvention include but are not limited to, carbon nanotubes, grapheneoxide, or ceramic based materials, which are generally not considerednaturally derived materials.

In a preferred embodiment of the present invention, the razor blade isformed from cellulose, cellulose-based particles and cellulose-basedcomposites.

As used herein, “cellulose nanocrystals” or “CNC” signify nanomaterialsderived from a cellulose. Cellulose nanocrystals, primarily obtainedfrom naturally occurring cellulose fibers, are biodegradable andrenewable in nature. For instance, cellulose material can readily beextracted from wood, hemp, cotton, linen, and other sources. The term“cellulose nanostructure” as used herein may include but is not limitedcellulose nanocrystal materials. As shown in FIG. 1, cellulosenanostructure of the present invention can be extracted from trees.

Accordingly, they serve as a renewable, sustainable and/orenvironmentally friendly material in the present invention as razorblades are generally disposed of after one or several uses.

The nanostructures of the present invention, such as cellulosenanocrystals or CNCs, have significant advantageous properties includingmechanical and chemical properties. For instance, in some instances, ithas been determined that individual cellulose nanocrystals (CNCs) have aYoung's modulus of 150 GPa. With diameters and lengths on the order of10 nm and 100 nm respectively, the materials of the present inventionproduce nanocomposites with nanoscale features such as a razor bladecutting-edge structure. In contrast, the materials of the prior art suchas conventional micron-scale fillers and metal powders, cannot producefeatures with nanoscale dimensions having optimal mechanical andchemical attributes.

Aspects of a cellulose nanostructure 20 of the present invention areshown in FIG. 2. The chemical structure of a cellulose chain 22 isdepicted in FIG. 2(a) having a pyranose ring with bonds. A cellulosemicrofibril 24 is depicted in FIG. 2(b) having disordered regions 24 aand crystalline regions 24 b. Cellulose nanocrystals 26 are depicted inFIG. 2(c). Cellulose nanocrystals are generally long, thin and slightlyoval shaped. This general shape is conducive to fabricating razor bladecutting edges as they can substantially fill in the area underneathwedge shaped tip.

Exemplary illustrations of a razor blade or formed cutting-edgestructure comprised of filled in cellulose nanostructures of the presentinvention is shown in FIGS. 3A, 3B, and 3C. In any of these embodiments,an electric of magnetic field can be applied in the process ofmanufacturing or molding cutting-edge structure or near the tip of thecutting-edge structure so as to cause the nanostructures (e.g.,cellulose nanocrystals or CNCs) to become concentrated at the tip ornear the interface of the gel and base structure of the presentinvention.

As can be seen in FIG. 3A, a razor blade cutting edge 30 a of thepresent invention has cellulose nanostructures 32 vertically arrangedwithin the razor blade cutting-edge structure. Cellulose nanostructures32 provide a robust cutting edge in that the vertical arrangement of thenanostructure provides shaving advantages as the nanostructures arealigned along the direction of the shave and substantially parallel tothe body 33 of the blade 30 a.

In FIG. 3B, a razor blade 30 b of the present invention has cellulosenanostructures 34 horizontally arranged within the razor bladecutting-edge structure. Cellulose nanostructures 34 provide a very sharpcutting edge in that the horizontal arrangement provides a highly filledarea of nanostructures at the tip such that the tip is resistant todamage from shaving. In FIG. 3C, a razor blade 30 c of the presentinvention has cellulose nanostructures 36 in a mixed or matrixed manner,some vertically aligned, some horizontally aligned, and some angled andoriented in various directions within the razor blade cutting-edgestructure. Cellulose nanostructures 36 provides a very sharp and robustcutting edge in that the mixed arrangement of nanostructures providesstability at the tip.

The cutting-edge structures of the present invention may also becomprised of other nanostructures and polymers.

As used herein, a polymeric material signifies a material that is formedof a polymer, the latter being a large, chain-like molecule made up ofmonomers, which are small molecules. Generally, a polymer can benaturally occurring or synthetic. In the present invention, preferredembodiments comprise naturally occurring or semi-synthetic polymers asopposed to synthetic polymers.

The polymer materials of the present invention generally can occur intwo forms or states. The first state may be a soft or fluid state andthe second state may be a hard or solid state. Generally, polymers aremolded or extruded when in the first state (e.g., liquid or soft) andsubsequently formed into an object that is in a second state (e.g., hardor solid). In some instances, the material is reversible (e.g., amaterial in the second state can be converted back to its first state)while in others, the polymerization is irreversible (e.g., the materialcannot be converted back to its first state).

For those polymeric materials where the second state is obtained fromthe first state via irreversible polymerization, the first state of thepolymeric material may generally be thought of as being a “precursor”for the second state of the polymeric material. As such, in the presentinvention, a polymeric material may be generated from a precursormaterial or a material in a first state.

The materials that are generally desired for the present inventioncutting-edge structures are materials in the first, soft or liquid,states which comprise monomers or short chain length (e.g., lowmolecular weight) polymers known as oligomers or both. Both monomers andoligomers are referred to herein as “precursors.” These precursors areconverted into long chain length polymeric material in the second, solidstate through a polymerization or cross-linking process, herein referredto as a curing process. Curing the precursor material can generally beachieved under the influence of heat, light, ionic or high energyradiation, or any combination thereof. After curing, the solid materialcomprises multiple components including polymer.

The novel cutting-edge material of the present invention is comprised ofseveral components. A first component is a naturally derived, renewable,or biodegradable material such as cellulose as described above.Preferably cellulose nanocrystals (CNCs) are utilized due to theirdesirable mechanical and chemical properties. An example of a preferredtype of cellulose nanocrystal that can be utilized in the presentinvention is shown in FIG. 2A-2C.

A second component of the novel cutting-edge material of the presentinvention comprises a solvent. The solvent is preferably an organicsolvent. Desirably, the solvent comprises components which are capableof dissolving polymers. In a preferred embodiment, the solvent comprisesdimethylformamide. Dimethylformamide is an organic compound with theformula (CH₃)₂NC(O)H. The solvent, while present initially, will beremoved and evaporated from the material to form a fully solid compositeas will be described herein.

A third component of the novel cutting-edge material comprises one ormore polymeric materials. The polymeric materials may comprise fromabout 10 percent to about 50 percent by weight of the composite of thecutting-edge material. The polymeric materials can be of any typeincluding but not limited to, natural, synthetic or semi-syntheticpolymers. In a preferred embodiment of the present invention, thepolymeric component of the material of the present invention comprisesepoxide. Some epoxides of the present invention can be obtained fromnaturally derived, renewable, or biodegradable sources.

An exemplary embodiment of the cutting-edge material used in the processof making a cutting-edge structure of the present invention is depictedand described in conjunction with FIGS. 11 and 12.

The present invention contemplates that all (e.g., 100%) orsubstantially all, of the novel cutting-edge material is obtained from anaturally derived, renewable, or biodegradable source by volumefraction.

The present invention contemplates that at least about 50 percent toabout 100 percent of the novel cutting-edge material is obtained from anaturally derived, renewable, or biodegradable source by volumefraction.

Desirably, about 90% of the cutting-edge structure is formed of amaterial that is obtained from a naturally derived, renewable, orbiodegradable source by volume fraction.

In contrast, the prior art discloses low-volume fraction (e.g., lessthan about 50%) fillers in a matrix that are substantially obtained fromnon-naturally derived or non-renewable sources. A disadvantage of theprior art is that, due to kinetic arrest of nanoparticle suspensions,most conventional nanocomposites are restricted to polymer-reinforcementapplications with these low volume fraction of nanoparticles. Largernanoparticle-to-polymer ratios require addition of solvent to allowdispersion and processing, but present the challenge of large volumetricshrinkage associated with solvent evaporation.

The present invention comprises a formulation that allowsnanoparticle-to-polymer ratios between about 50% to about 90%. As willbe described herein, the present invention comprises a dual cure (e.g.,UV and thermal) process which manages the solvent evaporation andshrinkage, enabling net-shape forming including sharp objects such ascutting-edge structures.

Mold Apparatus

The present invention comprises a base structure which is used to formthe novel cutting-edge structures of the present invention using thecutting-edge material described herein.

FIG. 4 depicts a cross-sectional view of base structure 40 used in thepresent invention. The base structure 40 in the present invention isutilized as a mold apparatus to form (or mold) a cutting-edge structuresuitable for use in making a razor, razor blade or razor cartridge.

In one embodiment, a base structure 40, as shown in FIG. 4, comprisestwo parts, an upper portion 41 and a lower portion 42. In an alternateembodiment of the present invention (not shown), base structure 40 maybe a single movable part or an integral part which cannot generally besplit into further parts. However, as the contact between the upper andlower portion is a significant aspect of the present invention as willbe described below, it may generally be more feasible to utilize a twopart base structure.

The upper and lower portions 41 and 42 can be of any size, shape anddimension. In a preferred embodiment of the present invention shown inFIG. 4, the upper portion 41 comprises a plunger structure and the lowerportion 42 comprises a cavity structure which the plunger structure ofthe upper portion mates with.

The plunger structure of the present invention can be comprised of anymaterial, including, but not limited to, one or more lubriciousmaterials, one or more plastic materials, one or more metals,low-coefficient of thermal expansion alloys such as Invar, metals coatedwith a polymer, such as PTFE, (e.g., often referred to as Teflon), orpolypropylene or silicones, or any combinations thereof. In a preferableembodiment of the present invention, the plunger structure is preferablycomprised of Teflon, or a Teflon-based, lubricious material. In analternate preferred embodiment of the present invention, the plungerstructure may also be comprised of a metal which is coated with alubricious material, such as Teflon or a Teflon-based material. It isdesirable that the entirety or at least a portion of the plungerstructure of the base structure comprises a lubricious surface (e.g.,Teflon coated) for the mold apparatus to perform optimally and inparticular for a release or separation of the plunger structure from thecavity structure during the process.

The plunger structure of the present invention preferably has agenerally cylindrical shape including a main body 41 a and a plungerelement 41 b. The plunger structure 41 also desirably includes one ormore angled surfaces 41 c and one or more relief portions 41 dpreferably disposed between the main body 41 a and the plunger element41 b.

The angles 41 c′ of the one or more angled surfaces 41 c of the plungerstructure can range from about 15 degrees to about 60 degrees, and morepreferably, angle 41 c′ is about 21.5 degrees.

The relief portion 41 d is shaped and sized sufficient to ensure a linecontact at the interface 46 between the plunger structure 41 and thecavity structure 42. Generally, as shown in FIG. 4, the relief portion41 d comprises an intermediate neck-like structure between the plungerbody and the plunger element, having smaller dimensions than either theplunger body or the plunger element. The plunger element 41 b of thepresent invention may desirably have smaller dimensions than the plungerbody but larger dimensions than the relief portion.

The plunger structure of the present invention preferably has anyfeasible dimensions to perform the manufacturing process of the presentinvention taking into account the dimensions of the desired cutting-edgestructure (e.g., inner diameter of the cutting-edge structure), thesetup of the base structure, and materials used for the plungerstructure. The plunger structure can have any height. The height of aplunger structure in one embodiment of the present invention is about 50mm. The plunger structure of the present invention may be hollow orsolid. The plunger structure coupled to the cavity structure of thepresent invention is capable of providing an cutting-edge structurehaving a circular shape having a diameter of about 10 mm diameter orless, preferably about 3 mm, and desirably not more than about 0.5 mm.

The cavity structure of the present invention can be comprised of anymaterial, including but not limited to, one or more plastic materials,one or more metals, one or more lubricious materials, or anycombinations thereof. Other materials are also contemplated in thepresent invention including but not limited to, cermets which aregenerally a ceramic-metal composite (e.g., Tungsten Carbide/Cobalt).Such materials can also be coated with a lubriocious release agent likeTeflon or silicones. In a preferable embodiment of the presentinvention, the cavity structure 42 is comprised of a metal material,desirably a material with a low coefficient of thermal expansion, suchas aluminum, steel, or Invar material. In an alternate embodiment of thepresent invention, the cavity structure 42 may be comprised of acombination of materials. For instance, the cavity structure may becomprised of a metal material which includes a plastic material or ametal material which is coated with a plastic or lubricious material,such as a polypropylene or Teflon material, respectively.

The cavity structure of the present invention is desirably a rigid orsemi-rigid structure so as to accommodate the force that will be appliedfrom the upper portion 41 (e.g., the plunger structure), as will bedescribed in more detail below.

The shape of the cavity structure of the present invention can be anyshape including but not limited to a frustum shape such as a conicalfrustum, a trapezoidal frustum or a pyramidal frustum or a cylindricalor other three-dimensional shape. A cavity structure 42 of the presentinvention having a conical frustum shape is shown in FIG. 4.

Regardless of overall shape, the cavity structure 42 of the presentinvention preferably includes an aperture 44 extending from an uppersurface or the top area 42 a of the cavity structure 42 into at least aportion of, or all the way through, the internal area 42 b of the cavitystructure 42. The shape of aperture 44 at the upper surface of thecavity structure is preferably a circular or round shape and as itextends into the cavity structure it can comprise a cylindrical,spherical or any other feasible shape. The present inventioncontemplates that the shape of aperture 44 in the present invention isdesirably substantially similar to that of the plunger element 41 b. Inthis way, the plunger element 41 b can be inserted into the aperture 44of the cavity structure as shown in FIG. 1 in accordance with thepresent invention. In addition, the cavity walls 42 c include one ormore angled or slightly chamfered surfaces 42 c′ extending into thecavity structure to provide for ease in accommodating and mating withthe plunger structure.

Between the mating surfaces or interface 46 of each portion 41 and 42 iswhere a cutting-edge structure 47 of the novel cutting-edge material isformed. In order for the cutting-edge structure 47 to be formed, bothupper and lower portions, or the plunger structure and cavity structure,respectively, along with the novel cutting-edge material, have to bepresent in the base structure 40 and in contact as shown in FIG. 5. Theplunger structure is forcefully inserted into the cavity structure. Indoing so, there is a line contact 48 that is formed at the interface 46between the plunger structure and the cavity structure. This linecontact 48 is an important aspect of the present invention as the linecontact formed at the interface 46 serves to form the sharp tip and edgeof the cutting-edge structure 47.

It should be noted that preferably, at least one of portions of the basestructure comprises a cylindrical three-dimensional shape to allow forthis line contact 48 to be formed. In the present invention, the plungerstructure is preferably formed as a generally cylindrical shape and thecavity structure has a conical frustum or trapezoidal shape.

Exemplary embodiments of discrete components of the base structure, theplunger structure 41 and the cavity structure 42 of the present inventonare shown separately in the photographic image in FIG. 5A.

With the pressure from the plunger structure at the aperture 44, acutting-edge material is pressed, embossed or shaped into a sharp edge.Though any shape is contemplated in the present invention, thecutting-edge structure 47 formed with the base structure 40 having acircular aperture comprises a ring or loop shape. An alternate preferredembodiment showing a base structure forming a linear cutting-edgestructure is described and shown in FIG. 8.

FIG. 6 depicts an illustration of a razor blade cutting edge structure60 of the present invention and its cutting-edge structure 47 formedutilizing the base structure 40 of FIGS. 4 and 5.

In FIG. 7, a photographic image 70 depicts an actual separated mold basestructure with the removal of the cavity structure showing only theformed cutting-edge structure 47 disposed along angled surfaces 41 c ofthe plunger structure 41. The ring or loop shape of the cutting-edgestructure 47 is formed. As can be seen in the photographic image 70 inFIG. 7, the cutting-edge structure 47 also comprises a dark brown color.This color is chemically generated, but other colors may be generated inthe process of the present invention.

FIG. 8 depicts a micrograph 80 of a portion of the cutting-edgestructure 47 produced with the base structure 40 of the presentinvention utilizing the novel cutting-edge material comprising cellulosenanostructures of the present invention.

As described above, a cutting-edge structure 47 having a loop shape isformed at a line contact 48 formed at the interface 46 of portions 41and 42.

The present invention also contemplates forming linear cutting-edgestructures. To form linear cutting-edge structures, rather than a loopor ring cutting-edge structure, the base structure 90 of the presentinvention may comprise an upper portion 91 having a cylindrical or rodshape while one or more lower portions 92 comprise a cavity structure ofany shape, preferably having a trapezoidal prism shape as shown in thefront and perspective views of FIGS. 9A and 9B, respectively. Cavitystructures 92 also comprise one or more angled surfaces 93. Anglesurfaces 93 comprise angles ranging from about 15 degrees to about 60degrees, and more preferably ranging from about 20 degrees to about 40degrees. These angled surfaces 93 of the cavity structure 92 accommodatethe cylindrical rod upper portion 91 as well as the novel cutting-edgematerial, as shown.

Cavity structure 92 and base structure 90 will together form two linecontacts 98 (e.g., one on each side) at the interface of theirrespective surfaces when contacting each other. Thus, in thisembodiment, two cutting-edge structures 94 a and 94 b (e.g., shown inFIG. 9A), can be formed at this line contact 98, each having a linearshape or a substantially linear shape, and each being formedsubstantially at the same time. This arrangement may be a time andcost-effective solution as it produces more than one cutting-edgestructure at one time. However, as shown in FIG. 9C, an alternateembodiment of a base structure 90 c of the present invention having anupper portion 91 c having a cylindrical or rod shape and lower portion92 c comprise a cavity structure of any shape, preferably having atrapezoidal prism shape, which may be two-sided, is also contemplated.Cavity structure 92 c and base structure 90 c will form a line contact98 c at the interface of their respective surfaces contacting eachother. Thus, in this embodiment, one cutting-edge structure razor blade94 c can be formed at line contact 98 c.

In FIGS. 9A-9C, the weight of the upper portion 91 a, 91 b, or 91 c(e.g, cylindrical rod shape) may provide the force that is needed toform the line contact for the linear cutting-edge structures 94, 94 b,and 94 c. The rod may be pre-loaded by gravity or be loaded using apress, driven mechanically (e.g., with a spring), or hydraulically. Inthis way, the rod may be capable of self-aligning due to the nature ofthe design.

To form the cutting-edge structure 47, the cavity structure is filledwith the novel material of the present invention. The processing of thematerial will be described in conjunction with the flow diagram shown inFIGS. 12A and 12B.

FIG. 9D depicts a linear shaped cutting-edge structure 94 d of thepresent invention which is suitable for use with a razor cartridge orblade unit.

A razor cartridge 100 having one or more cutting-edge structures orrazor blades 102 made of cellulose nanostructure (e.g., nanocrystal)materials 104 of the present invention can be assembled as shown in FIG.10. Cutting edge structures 102 depicted in FIG. 10 are preferably ofthe linear type as described herein. Razor cartridge 100 is similar torazor cartridges that are commercially available utilizing steel bladesand with plastic housing and frame components 106.

A razor cartridge 105 having one or more cutting-edge structures orrazor blades 139 made of cellulose nanostructure (e.g., nanocrystal)materials 110 of the present invention can be assembled as shown in FIG.10A. Cutting edge structures 139 depicted in FIG. 10A are preferably ofthe circular shape as described herein. Razor cartridge 105 is similarto razor cartridges that are commercially available utilizing steelblades and with plastic housing and frame components 108.

Process of Making Razor Blade Out of Novel Material

Referring to FIG. 11, and as described above, the novel cutting-edgematerial 110 of the present invention comprises several components. In apreferred embodiment, the cutting-edge material 110 comprises cellulosenanostructures 112, one or more oligomers or polymers 114, such as anepoxide, and a solvent 116, preferably an organic solvent, and morepreferably dimethylformamide.

Desirably, about 90 percent or greater of the material 110 is renewableor sustainable. The cellulose nanostructures 112 generally may representsubstantially all of the sustainable or renewable portion of thematerial 110. The cellulose nanostructures 112 and the solvent 116together may represent all or substantially all of the sustainable orrenewable portion of the material 110. The cellulose nanostructures 112and the solvent 116 together may account for about 60 percent to about90 percent of the sustainable or renewable portion of the material 110.

The material 111 may also comprise cross-linkers 115, thermal orultra-violet (UV) cross-linkers 114, or any combination thereof. Thecross-linkers serve to form covalent bonds between the cellulosenanostructure material and the polymer, as well as within the polymer.

The material 111 may also include at least one photoinitiator comprisingan ultra-violet light curing photoinitiator, a cationic photoiniatior, afree radical photoinitiator, a thermal photoiniator, or any combinationthereof. The thermal photoinitiator desirably comprises polyamine. Thecationic photoinitiator preferably comprises an epoxide.

The cutting-edge material 111 of the present invention is desirably in afirst state in the form of a physical gel.

Turning now to FIGS. 12A and 12B, a flow diagram 120 is shown outlininga more detailed description of the processing of the novel cutting-edgematerial 110 of the present invention to form a cutting-edge structure.The cutting-edge material 110 will transform from its first state as aphysical gel to a final state, that of a rigid, solid and sharpcutting-edge structure, such as the exemplary structures describedherein.

At step 121, a layer of a physical gel of the cutting-edge material ofthe present invention is deposited in a lower portion or cavitystructure 122. The gel is desirably deposited into an aperture 122 b ofthe cavity structure 122. The aperture 122 b may extend throughout thestructure 122 in that the structure is open at both ends with a largermouth at the top area 122 c of the cavity structure than at a bottomarea 122 d of the cavity structure 122. Aperture 122 b is shown having agenerally circular shape though any shape is contemplated in the presentinvention.

At step 123, the physical gel is cured. Preferably, the curing thatoccurs is an ultra-violet curing for a duration of one or more secondsto several minutes, as disclosed in co-pending U.S. Docket Number101328-562, U.S. application Ser. No. ______ filed on the same date Dec.12, 2019 as the present application, and U.S. Application Ser. No.62/780,187 filed on Dec. 14, 2018, entitled “Systems, Devices, andMethods for Bulk Processing of Highly-Loaded Nanocomposites,”incorporated herein in its entirety, including specification anddrawings.

After curing the physical gel 110, a chemical gel 124 is formed at step125 within the cavity structure. Steps 121 and 123, of depositing anamount (e.g., a layer) of physical gel and curing it to form a chemicalgel, can be repeated at step 126 as many times as necessary to fill thecavity structure with the desired amount of chemical gel to obtain thefinal structure. Desirably, the final structure has little tosubstantially no volatile components in part due to evaporation of anyvolatile material resulting in convective flows once the plunger isinserted into the cavity structure thereby forming the chemical gel.

The chemical gel 124 of the present invention is comprised of cellulosenanocrystals, and polymer that are partially covalently bonded. Thechemical gel also comprises solvent. The chemical gel 124 is considereda viscoelastic solid structure. This structure is desirable in thepresent invention because it is capable of being molded into one or moreshapes.

At step 127, the solvent within the chemical gel is evaporated by dryingthe chemical gel at room temperature in air or in vacuum. As a result, adried chemical gel 128 is formed. This process step is desirable (e.g.,to remove the solvent by evaporation) as it was determined in a novelaspect of the present invention process that removal of the solventminimizes microscale phase separation and volumetric shrinkage in thenext step of cure.

At step 129, the plunger structure 130 is inserted, desirably at roomtemperature, into the aperture 122 b of the cavity structure andcontacts the dried chemical gel 128. The plunger structure 130 is pressfit or embossed into the cavity structure 122 and plunger element 130 aat the front of the plunger structure is shaped to assist in wedging theplunger structure 130 into the aperture 122 b while abutting the angledsurfaces 122 a of the cavity structure 122.

A line contact 131 is formed at the interface 132 between the plungerstructure and the cavity structure at step 133. The line contact maygenerally be at the surface of the aperture of the cavity structure. Ascan be seen at step 133 which depicts a front and perspective front viewof the base structure 134, a cutting-edge structure 135 has now beenformed from the dried chemical gel 128.

The plunger structure 130 is inserted with sufficient force to form ormold the dried chemical gel into the sharp shape of a cutting-edgestructure having a loop or ring shape of the present invention. Reliefportion 130 b ensures that the dried chemical gel is embossed down to apoint assisting in obtaining the cutting-edge structure with a desiredtip radius (e.g., less than 1 μm) for optimal shaving performance. Inaddition, any remaining dried chemical gel 128 displaced by the plungerstructure may remain in the inner walls of the plunger or cavitystructure or may be displaced externally to the structures. Anyremaining dried chemical gel 128 (not shown), not a part of thecutting-edge structure, can be disposed of, recycled, or optionallycured using the process herein as a reference specimen.

Depending on the design of the base or mold structure, any cutting-edgestructure shape can be produced. The present invention contemplates thata loop shaped cutting-edge structure, a linear cutting-edge structure orany combination thereof, can be formed using the process describedherein. Subsequently, at step 136, the formed dried chemical gel (nowcutting-edge structure 135) is heated from room temperature (e.g., 25degrees Celsius) to about 180 degrees Celsius to complete the curing andcompletely harden the cutting-edge structure.

This heating step 136 may occur in several steps of varying durationwhere the temperature is incrementally increased. For instance, thetemperature may rise from room temperature to about 50 degrees Celsiusto about 100 degrees Celsius, preferably about 80 degrees Celsius, andin a subsequent step, from 80 degrees Celsius to about 120 degreesCelsius. This dual stage thermal cure can be performed at differentdurations. For instance, as shown in FIG. 12, a first heating step 136may occur at 80 degrees Celsius and may have a duration of about 8 hourswhile a second heating step 137 may occur at 130 degrees Celsius and mayhave a duration of about 4 hours.

Optionally, steps 136 and 137 can be performed in an autoclave atpressure greater than atmospheric pressure to ensure further compactionof the material 135 forming the final cutting-edge structure 139.

The tip radius of the cutting-edge structure produced by the presentinvention process is desirably in the range of less than about 1micrometer. The hardness of the cutting-edge structure formed, such mayreach greater than 100 MPa, preferably greater than 500 MPa aftercuring.

Due to the nanoscale structure of the desired cutting-edge, shrinkage isnot desirable. Accordingly, the avoidance of shrinkage and phaseseparation is an important consideration and is achieved by severalprocess steps described herein. For instance, step 123 (e.g., the curingof the physical gel material to form a chemical gel material), step 127(e.g., vacuum/evaporation of solvent) and steps 136 and 137 (final cureby heating) each or together assist in providing a final structure withminimal shrinkage and phase separation.

At step 138, the plunger structure and the cavity structure can beseparated to extract the molded cutting-edge structure 139. As the twoportions were joined or contacted together by force, the base structuregenerally has to be opened or split apart in order to remove thecutting-edge structure 139.

The final cutting-edge structure 139 can be inserted into a razorcartridge for use in shaving. FIGS. 10 and 10A depict multiple finalcutting-edge structures of the linear type and the circular type,respectively inserted into a razor cartridge 100 and 120.

After final cutting-edge structure 139 is formed and prior to insertioninto a razor cartridge, the final cutting edge structure 139, which maybe circular shaped as shown in FIG. 12B or of any shape (e.g., linearshaped as in FIG. 10), may be coated with one or more materials. Asshown in FIG. 14A, one or more hard coatings 174 can be applied on thecutting-edge structure 172 as shown in the group 170 of multiple cuttingedge structures. The hard coating provides additional strength tostructure or to provide a radius of curvature of the blade edge betweenabout 20 nanometers and about 100 nanometers after deposition of thehard coating. The hard coating can comprise diamond, diamond-likecarbon, amorphous diamond, boron nitride, niobium nitride, siliconnitride, chromium nitride, zirconium nitride, titanium nitride, siliconcarbide, alumina, zirconia, or any combination thereof.

As shown in the group 180 of multiple cutting-edge structures of FIG.14B, one or more soft coatings 182 can also be deposited on acutting-edge structure 172 on all or some portion of the hard coating174 of FIG. 14A. The soft coating may be an outer layer on thecutting-edge structure and is used to provide reduced friction duringshaving. The soft outer layer may be a polymer composition or a modifiedpolymer composition. The polymer composition may be polyfluorocarbon. Asuitable polyflourocarbon is polytetrafluoroethylene (PTFE), sometimesreferred to as a telomer. This material is a nonflammable and stable drylubricant that consists of small particles that yield stabledispersions. It may generally be furnished as an aqueous dispersion ofabout 20% solids by weight and can be applied by dipping, spraying, orbrushing, and can thereafter be air dried or melt coated. The finalcutting-edge structure of the razor blades of the present invention maybe heated prior to application of the soft coating/outer layer. In oneembodiment, the cellulose nanocrystal-based razor blades are heated toabout 120 degrees Celsius before an aqueous dispersion of PTFE is spraycoated thereon. The soft coating layer is preferably less than about5,000 angstroms and could typically be about 1,500 angstroms to about4,000 angstroms, and can be as thin as about 100 angstroms, providedthat a continuous coating is maintained.

While the methods of manufacturing described herein have been referredto with primary reference to a single cutting-edge structure (e.g.,razor blade), the methods are easily applicable to the manufacture ofmultiple cutting-edge structures simultaneously.

Turning now to FIGS. 13A to 13C, an alternate base structure 140 of thepresent invention is shown. Depicted in FIGS. 13A to 13C is a basestructure 140 having multiple plunger structures 142 and multiple cavitystructures 144. Base structure 140 includes an upper main platform 141,on which an upper base portion 148 is disposed which carries the plungerstructures 142. As shown, the eight plunger structures are all containedwithin upper base portion 148. Base structure 140 includes a lower mainplatform 143, on which a lower base portion 147 is disposed whichcarries the eight cavity structures 144. As shown, the eight cavitystructures 144 are all contained within lower base portion 147.

In FIGS. 13A to 13C, a base structure incorporates eight plungerstructures 142 and eight cavity structures 144 which are utilized inaccordance with the methods described herein. Manufacture of theplurality of cutting-edge structures (e.g., razor blades) follows theprocess of FIG. 12A and FIG. 12B but would necessarily include morecutting-edge material (not shown), filling each of the eight individualcavity structures 144, and then pressed into the cavity structure by theplunger structures aligned above them. The pressing force occurs at thesame time (if more than one) or in sequence (if only one). With thisforceful insertion, the plunger structures substantially simultaneouslyemboss the cutting-edge material which in turn, produces several sharpcutting-edges. After such a “batch” manufacture of the plurality ofcutting-edge structures such as razor blades within the base structure,the cutting-edge structures may be separated as described above inconjunction with FIG. 12A and FIG. 12B in preparation for furtherassembly into razor cartridges. It should be noted that the size of thebase structure 140 can vary depending on the size of the cutting-edgestructures desired, and generally may be larger than the base structureutilized for forming a single cutting edge-structure as described inconjunction with FIG. 12A and FIG. 12B.

Turning to FIG. 14, a plurality of razor blades may be formed in groups150, e.g., clustered together in groups of multiple cutting-edgestructures 151, within a small frame 152. The frame 152 is anon-cutting-edge structure while the razor blades are cutting-edgestructures. The frame has a generally rectangular shape and for ease indiscussion are referred to herein as blade boxes 154. The plurality ofrazor blades 150 can be manufactured in this clustered organization toreduce downstream process steps in the shaving razor system assembly.The blade boxes 150 may have four individual razor blades 151, asillustrated, enclosed by a frame 152. Blade boxes 154 can bemanufactured identically or they can be different, such as each boxhaving differences in blade spacing, included blade angles, number ofblades, orientation of the blades, and the like. The differences can bemade via changes to the various method steps described above, such asutilizing different templates and pressing in different orientations,and the like. A blade box 154 can be removed from the base structure 140or any of the upper or lower portions in the same manner as describedabove, but such that the self-contained blade box 154 is a singularunitary part. In FIG. 15, a blade box 154 of the present invention isinserted into an opening 161 in the housing 162 of a razor cartridge 160and secured therein or be formed into a razor cartridge entirely at theoutset (not shown).

Assembling the razor cartridge in such a manner eliminates the somewhattime consuming or difficult steps of affixing each individual razorblade to a blade support or to a housing, inserting each bladesupport-razor blade pair or each blade in the razor cartridge housing,and aligning each separate razor blade to the desired blade height,angle, and spacing. By utilizing the method described herein, theplurality of razor blades are aligned and secured in the blade box,thereby eliminating the need to affix individual blade supports and thedifficult process of aligning 4 or more separate razor blades into therazor cartridge housing. While FIGS. 14 and 15 illustrate blade boxes154 having 4 razor blades, it is to be understood that any number ofrazor blades can be clustered or formed together, such as 2, 4, 5, ormore.

As mentioned, while the blades illustrated in the figures thus far havedescribed circular and linear cutting-edge structures (e.g., razor bladeedges), other blade shapes and edge patterns can be produced by themethods described herein including a mixture of different cutting-edgestructure shapes formed within one “blade box.”

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numerical values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm.”

Every document cited herein, including any cross referenced or relatedpatent or application, is hereby incorporated herein by reference in itsentirety unless expressly excluded or otherwise limited. The citation ofany document is not an admission that it is prior art with respect toany invention disclosed or claimed herein or that it alone, or in anycombination with any other reference or references, teaches, suggests ordiscloses any such invention. Further, to the extent that any meaning ordefinition of a term in this document conflicts with any meaning ordefinition of the same term in a document incorporated by reference, themeaning or definition assigned to that term in this document shallgovern.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

What is claimed is:
 1. A cutting-edge structure comprising one or morenaturally derived materials.
 2. The cutting-edge structure of claim 1further comprising one or more solvents, one or more renewablematerials, one or more biodegradable materials, and one or morepolymeric materials.
 3. The cutting-edge structure of claim 1 whereinsaid one or more naturally derived materials comprise cellulosenanostructures.
 4. The cutting-edge structure of claim 3 wherein saidcellulose nanostructures are cellulose nanocrystals.
 5. The cutting-edgestructure of claim 2 wherein said one or more solvents comprise anorganic material.
 6. The cutting-edge structure of claim 5 wherein saidorganic material comprises dimethylformamine.
 7. The cutting-edgestructure of claim 2 wherein said at least one polymeric materialcomprises one or more epoxides.
 8. The cutting-edge structure of claim 1wherein said cutting-edge structure comprise a brown color.
 9. Thecutting-edge structure of claim 1 wherein a shape of said cutting-edgestructure is circular, linear, or any combination thereof.
 10. Thecutting-edge structure of claim 1 wherein 100% of said cutting-edgestructure is comprised of said one or more naturally derived materials.11. The cutting-edge structure of claim 1 wherein 100% of saidcutting-edge structure is comprise of one or more renewable sources. 12.The cutting-edge structure of claim 1 wherein about 50% to about 100% ofsaid cutting-edge structure is comprised of naturally derived materialsby volume fraction.
 13. The cutting-edge structure of claim 1 whereinabout 50% to about 100% of said cutting-edge structure is comprised ofrenewable sources by volume fraction.
 14. The cutting-edge structure ofclaim 2 wherein said cutting-edge structure is comprised of about 50% toabout 100% of said one or more naturally derived material by volumefraction.
 15. The cutting-edge structure of claim 2 wherein said one ormore solvents and said one or more naturally derived materials comprisea majority of materials of said cutting-edge structure.
 16. Thecutting-edge structure of claim 1 further comprising a tip radius ofless than about 1 um.
 17. The cutting-edge structure of claim 1 whereinsaid cutting-edge structure is biodegradable.